Aggression refers to a set of behaviors characterized by intense anger, hostility, or violent behaviour towards others, often accompanied by harmful social interactions and an intention. Aggression is behavior aimed at opposing or attacking something or someone. Though often done with the intent to cause harm, some might channel it into creative and practical outlets. The meaning of aggression is a forceful action or procedure (such as an unprovoked attack) especially when intended to dominate or master. How to use aggression in a sentence.